With more than 27,000 confirmed cases of swine flu in 74 countries, the A(H1N1) virus is set to be declared an official global pandemic by the World Health Organisation (WHO). Currently at phase five on the pandemic scale, if swine flu is elevated to phase six it would require largescale production of vaccines. Phase six would represent the fact that the virus has spread to at least two global regions. With cases in North America, Japan, Australia and Europe, this is likely to be the case and may even lead to the declaration of an epidemic. "Once I get indisputable evidence I will make the announcement," said Dr Margaret Chan, head of WHO, after calling an emergency meeting of flu experts. Pharmaceutical companies have indicated that it could be six months before enough of the vaccine can be produced for global use.